Pin-tumbler lock



F. E. THOMPSON- PIN TUMBLE nPPucmou min I? LOCK. MN. 30. 1920.

Patented May 18, 1.920.

UNITED STATES PATENT OFFICE.

FRANK E. THOMPSON, OF STAMFORD, CONNECTICUT, ASSIGNOR TO THE YALE &TOWNE MANUFACTURING COMPANY, OF STAMFORD, CONNECTICUT.

PIN-TUMBLEB LOCK.

Specification of Letters Patent.

Patented. May 18, 1920.

Application flied January 30, 1920. Serial No. 355,034.

To all whom it may com/cm:

Be it known that I, FRANK E. THOMPSON, a citizen of the United States,and a resident of Stamford, in the county o-fFairfield and State ofConnecticut,'have invented certain new and useful Improvements inPin-Tumbler Locks; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it a pertains to make and use thesame.

y invention relates to an improvement in pin tumbler locks.

in pin tumbler looks, as ordinarily constructed, when a key is beinginserted in the plug, the beveled surfaces on the end of the key and oneach of the bittings or angles raise the pins, each in its respectivepin hole in the plug and also force the lower end of the pin backagainst the rear face of the pin hole, and as the pin is carried up bythe advancing key, it causes a wearing action on both the pin and itspin hole. As the key is withdrawn from the plug, this action isreversed, bringing the wear upon the front surface of the pin hole.

This action is not so serious when a key with a comparatively thin crosssection is used, but in many instances it is desirable to so slot thekey plug that keys differing in cross section may enter the lock andoperate the pin tumblers. This however necessitates the employment of awide slot which is nearly as wide as the diameter of the pin tumblers,thus necessarily leaving the latter with but a limited support at theirfront and rear surface in the plug, so that when the key is inserted andwithdrawn as above explained, wear between the tumblers and thesupporting surface in the plug for the latter soon impairs theefliciency of the lock.

The object of the present invention is therefore to provide means fortaking the strain and. consequent wear from the tumblers and the wallsof the holes in the plug in which they are mounted, and it consists inthe parts and combination of parts and in the details of construction aswill be more fully explained and pointed out in the claims.

In the accompanylng drawings; Figure 1 is a view of a lock partly insection and partly in elevation embodying my invention; Fig. 2 is anenlarged View of a portion of the key plug, the tumblers and a part ofthe key; Fig. 3 is a view in section on the line {LL-58 of Fig. 2, andFig. 4 is a view in horizontal section through one of the tumlilers andshowing the key slot in the plug and the restricted l'ienring for thetumblers.

5 represents the cylinder of a pin tumbler lock and 6 is the plugmounted to turn in the latter in the usual and well known manner. Thecylinder is provided with holes or recesses arranged to aline withsimilar holes in the plug for the reception of the pin tumblers T whichare of the well known construction and are operated. by a key 8 in theusual and well known manner. The key slot in the plug 6 is comparativelywide to receive keys differing in cross section, thus producing a slotwhich is nearly as wide as the diameter of the pin tumblers, so that theportions of the tumblers projecting into the key slot have but a limitedbearing or support at diametrically opposite points as shown at 9 inFig. 1.

the key is entered into and withdrawn from the plug 6, the tumblers areforced first back and then forward by the contact of the lower ends ofthe tumblers with the angles or the bittings on the key 8, and thisaction comliiined with the vertical movements of the tumblers soon wearthe plug and tumblers and produce a looseness between the parts whichinterferes with the operation of the lock and soon renders it worthless.

To overcome this trouble I provide each tumbler with a guiding pin 10projecting at opposite sides and located adjacent its lower end asshown. These guiding pins are located at right angles to the directionof the in and out movement of the key, and rest and move in grooves 11formed in the plug (3, the lower ends of the said grooves in someinstances forming stops for limiting the downward movements of thetumblers and for holding them in proper position with their lower endswithin the key slot so as .to be engaged and successively raised as thekey is passed into the slot. If desired the tumblers instead of beingsupported by the pins resting on the bottoms of the grooves may drop soas to rest in their normal manner at the bottoms of the tumbler holes inthe plug. These pins bearing against the walls of the grooves take allthe wear from the tumblers and the walls surrounding the 'latter andabsolutely prevent any movement of the tumblers that could cause them tobind in the holes or recesses.

As; the key is entered in the key slot the tumblers are successivelyraised, ride over the angle or bittings of the key and drop into theirproper seats on the latter, and when the key is removed they drop downso that their lower ends are in the key slot and in position to tbeengaged by the key and are so held by the pins ll) resting on the bottomwalla of the 'rooves 11 or at the bottoms of the tumbler holes in theplug.

Having fully described my invention What I claim as new and desire tosecure by Letters-Patent, is

1. In a pin tumbler lock, the combination ol' :1 cylinder, a plug havinga key slot, a pin tumbler for looking the plug against rotation in thecylinder and means projecting from the tumbler and resting in grooves inthe plug,- for preventing the tumbler From binding.

2. ln :1 pin tumbler lock, the combination of a l-ylinder, a plug havinga key slot, :1

pin tumbler and pins projecting from the tumbler at opposite sides ofthe latter and resting and moving in grooves in the plug. il. in a pintumbler lock, the eombination of a cylinder, a plug having a key slot, apin tumbler. and pins projecting from the tumbler at right angles to thedirection oi. the length ol' the key slot and resting and moving ingrooves formed in the plug.

ln a pin tumbler lorlg the combination of a cylinder, a plug; having akey slot, a pin tumbler, pine projecting from the latter at oppositesides and in a direction to take the strain imparted to the tumbler bythe in and out movement of the key, and guides for the said pins thesaid guides exteni'ling down into the key slot.

ln testimony whereof, l have signed this speeili -ation in the presenceof two subscriblltJf \vitneeseq.

FRANK W itnessen Hiuuins A. lmnnY. JUIJUH A. Wns'r.

Ill

